def calculate_discounted_bill(bill_amount):
    # This function calculates the final bill amount after applying the appropriate discount.
    # 此函数用于计算应用适当折扣后的最终账单金额。
    if bill_amount >= 200:
        return bill_amount * 0.85
    elif bill_amount >= 100:
        return bill_amount * 0.9
    else:
        return bill_amount
    pass

def main():
    # Prompt the user to enter the bill amount
    # 提示用户输入账单金额
    bill_amount = float(input("Please enter the bill amount in yuan: "))
    # Call the calculate_discounted_bill function
    # 调用 calculate_discounted_bill 函数
    final_bill = calculate_discounted_bill(bill_amount)
    # Print the final bill amount
    # 打印最终账单金额
    print(f"The final bill amount after discount is {final_bill} yuan.")


if __name__ == "__main__":
    main()